1. Field of the Invention
The present invention relates to an evaporative gas treating system for humidifying and cooling a gas stream.
2. Description of the Prior Art
The prior art discloses numerous evaporative gas treating systems for maintaining the temperature and humidity of an air stream in a variety of applications such as conditioning the air circulated through industrial paint spray booths, cooling factory work stations, and humidifying the inlet air supplies for gas turbines.
In installations of this type, it is necessary to very closely control the temperature and humidity of relatively large air flows. Typically, the air stream is circulated through an evaporating section including one or more fiberous media pads which are saturated with water which evaporates into the air stream to increase its humidity and lower its temperature. One of the more common ways of varying the extent of humidification effected by this type of arrangement has been to vary the flow of water into one or more of the media panels. However, in this type of arrangement the water flow must be very closely controlled to compensate for changing ambient conditions as well as to maintain the efficiency of the system. For example, if too little water is fed into the media, the air stream will not reach the desired humidity or temperature levels. Alternatively, oversaturation of the media and uneven water distribution in the media panels can cause excessive water droplet carry-over into the air stream requiring the use of mist eliminators or the like to remove the water droplets downstream from the evaporating section such as provided in the cooling and humidifying system shown in U.S. Pat. No. 2,904,254. Moreover, when water is added to saturated media panels a substantial steam of water flows straight through the panels. This water must be collected and either drained from the system or pumped back to the pads and recirculated. In larger installations, it is usually essential to recirculate the excess water to maintain the operating costs for the unit within reasonable limits notwithstanding the expense and additional complexity resulting from the installation and maintenance of an additional pumping system.